^Singer O, McCune WJ. Update on maintenance therapy for granulomatosis with polyangiitis and microscopic polyangiitis. Current Opinion in Rheumatology. May 2017, 29 (3): 248–253. PMID 28306595. S2CID 35805200. doi:10.1097/BOR.0000000000000382.
^World Health Organization. World Health Organization model list of essential medicines: 21st list 2019. Geneva: World Health Organization. 2019. hdl:10665/325771. WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO.
^ 11.011.111.211.3Patel AA, Swerlick RA, McCall CO. Azathioprine in dermatology: the past, the present, and the future. Journal of the American Academy of Dermatology. September 2006, 55 (3): 369–389. PMID 16908341. doi:10.1016/j.jaad.2005.07.059.
^Sandborn WJ. Azathioprine: state of the art in inflammatory bowel disease. Scandinavian Journal of Gastroenterology. Supplement. 1998, 225 (234): 92–99. PMID 9515759. doi:10.1080/003655298750027290.
^Biancone L, Tosti C, Fina D, Fantini M, De Nigris F, Geremia A, Pallone F. Review article: maintenance treatment of Crohn's disease. Alimentary Pharmacology & Therapeutics. June 2003, 17 (Suppl 2): 31–37. PMID 12786610. S2CID 23554085. doi:10.1046/j.1365-2036.17.s2.20.x.
^Chocair P, Duley J, Simmonds HA, Cameron JS, Ianhez L, Arap S, Sabbaga E. Low-dose allopurinol plus azathioprine/cyclosporin/prednisolone, a novel immunosuppressive regimen. Lancet. July 1993, 342 (8863): 83–84. PMID 8100914. S2CID 13419507. doi:10.1016/0140-6736(93)91287-V.
^Sparrow MP, Hande SA, Friedman S, Lim WC, Reddy SI, Cao D, Hanauer SB. Allopurinol safely and effectively optimizes tioguanine metabolites in inflammatory bowel disease patients not responding to azathioprine and mercaptopurine. Alimentary Pharmacology & Therapeutics. September 2005, 22 (5): 441–446. PMID 16128682. S2CID 9356163. doi:10.1111/j.1365-2036.2005.02583.x.
^Sparrow MP, Hande SA, Friedman S, Cao D, Hanauer SB. Effect of allopurinol on clinical outcomes in inflammatory bowel disease nonresponders to azathioprine or 6-mercaptopurine. Clinical Gastroenterology and Hepatology. February 2007, 5 (2): 209–214. PMID 17296529. doi:10.1016/j.cgh.2006.11.020.
^Ansari A, Patel N, Sanderson J, O'Donohue J, Duley JA, Florin TH. Low-dose azathioprine or mercaptopurine in combination with allopurinol can bypass many adverse drug reactions in patients with inflammatory bowel disease. Alimentary Pharmacology & Therapeutics. March 2010, 31 (6): 640–647. PMID 20015102. S2CID 6000856. doi:10.1111/j.1365-2036.2009.04221.x.
^Cleary BJ, Källén B. Early pregnancy azathioprine use and pregnancy outcomes. Birth Defects Research. Part A, Clinical and Molecular Teratology. July 2009, 85 (7): 647–654. PMID 19343728. doi:10.1002/bdra.20583.
^Elion GB, Callahan SW, Hitchings GH, Rundles RW. The metabolism of 2-amino-6-[(1-methyl-4-nitro-5-imidazolyl)thio]purine (B.W. 57-323) in man. Cancer Chemotherapy Reports. July 1960, 8: 47–52. PMID 13849699.
^Thiersch JB. Effect of 6-(1'-methyl-4'-nitro-5'-imidazolyl)-mercaptopurine and 2-amino-6-(1'-methyl-4'-nitro-5'-imidazolyl)-mercaptopurine on the rat litter in utero. Journal of Reproduction and Fertility. December 1962, 4 (3): 297–302. PMID 13980986. doi:10.1530/jrf.0.0040297.
^Murray JE, Merrill JP, Harrison JH, Wilson RE, Dammin GJ. Prolonged survival of human-kidney homografts by immunosuppressive drug therapy. The New England Journal of Medicine. June 1963, 268 (24): 1315–1323. PMID 13936775. doi:10.1056/NEJM196306132682401.
^Henry ML, Sommer BG, Ferguson RM. Beneficial effects of cyclosporine compared with azathioprine in cadaveric renal transplantation. American Journal of Surgery. November 1985, 150 (5): 533–536. PMID 2998215. doi:10.1016/0002-9610(85)90431-3.
^Modry DL, Oyer PE, Jamieson SW, Stinson EB, Baldwin JC, Reitz BA, Dawkins KD, McGregor CG, Hunt SA, Moran M. Cyclosporine in heart and heart-lung transplantation. Canadian Journal of Surgery. Journal Canadien de Chirurgie. May 1985, 28 (3): 274–80, 282. PMID 3922606.
^Woodroffe R, Yao GL, Meads C, Bayliss S, Ready A, Raftery J, Taylor RS. Clinical and cost-effectiveness of newer immunosuppressive regimens in renal transplantation: a systematic review and modelling study. Health Technology Assessment. May 2005, 9 (21): 1–194. PMID 15899149. doi:10.3310/hta9210.